SplineTest: calculateSteps(): use std::lround(), maybe fixes on 32-bit?
SplineTest: calculateSteps(): use std::lround(), maybe fixes on 32-bit?

LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed